performance of new diffuser design for an axial flow pump
TRANSCRIPT
Faculty of Engineering & Information Technology
Performance of New Diffuser Design for an Axial Flow Pump
By; Robert F Rosier
Masters in Engineering (Research) C03017
Supervisor: Dr Phuoc Huynh
CERTIFICATE OF ORIGINAL AUTHORSHIP
I certify that the work in this thesis has not previously been submitted for a degree nor has it been
submitted as part of requirements for a degree except as fully acknowledged within the text.
I also certify that the thesis has been written by me. Any help that I have received in my research
work and the preparation of the thesis itself has been acknowledged. In addition, I certify that all
information sources and literature used are indicated in the thesis.
Signature of Student:
Date:
Abstract
i
Abstract In an axial-flow pump unit, energy is lost from the pump system due to the swirl of the liquid
between the vanes and leaving the stator. A combined stator-diffuser has been designed for the
purpose to reduce this swirl and the corresponding loss of energy. Previous experimental
investigations indicated that the new stator-diffuser design does reduce the swirl still present in the
flow exiting from the pump unit when compared with a conventional design wherein the stator is
followed by a separate diffuser. However the efficiency of the modified pump unit was slightly
reduced. One of the reasons for this reduction in efficiency has been identified where a sudden
enlargement at the outlet of the diffuser introduces secondary flow creating large fluid swirl.
To reduce the secondary flow dimensional, theoretical, computational fluid dynamics (CFD) and
experimental measurements have been performed to determine the performance effects of the new
design diffuser combined with an additional tail piece. The tail piece is fitted to the outlet of the
new diffuser to eliminate the sudden enlargement. Theoretical calculations determined that the five
vane impeller did not match the new diffuser, whereas the eight vane impeller did match the new
diffuser design. Impellers with five and eight vanes were used during laboratory testing.
CFD and laboratory experiments were performed to verify that the tail piece addition would
produce improved performance. The theory was confirmed from the experiments that the five vane
impeller is not the correct impeller for use with the new diffuser with the tail piece however testing
with the eight vane impeller efficiency improved by 3.9%, when compared to the standard pump
test.
ii
Acknowledgements
iii
Acknowledgments Firstly I would like to thank Bruce Mackay who not only encouraged me but gave me the
opportunity to return to and take up studies at university.
It has been from working with pump engineers such as Ron Palgrave, Vic Kinder, Peter Smith
and David Manson whose combined engineering knowledge always encouraged me to want to
know more about hydraulic design.
Thank you to Dr Phuoc Huynh who offered and gave me the opportunity to take up this
research. I have learnt so much and improved my engineering capabilities during the course of
this work. Thanks also to Vahik Avakian who helped with the laboratory testing, numerous test
rig repairs and advice. Also thanks to Florin Voicu and Dr. Luis Moscoso from Weir for their
help and advice.
Finally, thanks for the support and patience from my wife Merrin and our children Ella and Taj.
iv
Nomenclature
v
Nomenclature Symbol Description Unit
Q Flowrate L/s
H Head m
Hp Pumping head m
HL Head loss m
p Pressure Pa
NPSH Net Positive Suction Head m
v Velocity m/s
vr Velocity reduced m/s
C Absolute velocity m/s
Cm Axial velocity m/s
Cu Tangential absolute velocity m/s
W Relative velocity m/s
Wu Tangential relative velocity m/s
L Lift
CL Lift coefficient
D Drag
CD Drag coefficient
ρ Density kg/m3
g Gravity m/s2
η Efficiency
N Rotational Speed rpm
Ns Specific speed
A Area m2
d Diameter m
E Energy J
Re Reynolds number
P Power W
Pp Pump input power W
Pw Pump output power W
t Time s
T Torque Nm
U Mean velocity m/s
V Volume m3
z Height above reference plane m
Nomenclature
vi
λ Pipe friction loss coefficient
ω Angular velocity rad/s
Lr Impeller radial length m
l Length m
b Outlet width m
BEP Best efficiency point
F force N
m mass kg
β Outlet angle
α Inlet angle °
σ Solidity
Contents
vii
Table of Contents
1 Introduction ............................................................................... 1
2 Literature Review ...................................................................... 3
2.1 General Pump Introduction ......................................................................... 3
2.1.1 Pump Classification .................................................................................................. 3
2.1.1.1 Pump Specific Speed ........................................................................................ 4
2.1.2 Axial Flow Pumps ..................................................................................................... 6
2.1.3 Axial Pump Capabilities ........................................................................................... 6
2.1.4 Axial Pump Assembly .............................................................................................. 8
2.1.4.1 Axial Flow Pump Major Components ............................................................ 10
2.1.4.1.1 Suction Bell ............................................................................................... 10
2.1.4.1.2 Impeller ..................................................................................................... 11
2.1.4.1.3 Bowl (Stator) and Diffuser ........................................................................ 13
2.1.5 Axial Pump Performance ........................................................................................ 16
2.1.5.1 Calculating Pump Performance....................................................................... 17
2.1.5.1.1 Pump Pressure ........................................................................................... 17
2.1.5.1.2 Pump Input Power (Pp).............................................................................. 18
2.1.5.1.3 Pump Output Power (Pw) .......................................................................... 18
2.1.5.1.4 Pump Efficiency ........................................................................................ 18
2.2 Theoretical Axial Pump Design ................................................................ 19
2.2.1 Velocity Triangles ................................................................................................... 20
2.2.2 Streamlines .............................................................................................................. 22
2.2.3 Boundary Layer....................................................................................................... 22
2.2.4 Impeller Vane Shape ............................................................................................... 23
2.2.5 Turbulent and Secondary Flow ............................................................................... 25
2.2.6 Vane Tip Clearance ................................................................................................. 26
2.2.7 Pump Stall ............................................................................................................... 27
2.2.8 Impeller Design ....................................................................................................... 29
2.2.8.1 Impeller Hub Ratio.......................................................................................... 29
2.2.8.2 Number of Impeller Vanes .............................................................................. 30
2.2.8.3 Impeller Vane Length ..................................................................................... 30
Contents
viii
2.3 Pump Stator and Diffuser .......................................................................... 31
2.3.1 Diffuser Design........................................................................................................ 31
2.3.2 Diffuser Vane Design Theory .................................................................................. 32
2.3.2.1 Diffuser Guide Vanes ...................................................................................... 33
2.3.2.2 Diffuser Efficiency .......................................................................................... 34
2.3.2.2.1 Axial Distance ........................................................................................... 35
2.3.2.2.2 Diffuser Vane Length and Number of Vanes ............................................ 35
2.4 Previous Research Review ........................................................................ 36
2.4.1 Previous Test Comparisons ..................................................................................... 36
3 Component Investigation ........................................................ 39
3.1 Part Measurement ...................................................................................... 39
3.1.1 Coordinate Measuring Machine (CMM) ................................................................. 39
3.1.1.1 Hard Probe Measurement ................................................................................ 41
3.1.1.2 Laser Probe Measurement ............................................................................... 41
3.1.2 CMM Measurement Results .................................................................................... 42
3.1.2.1 Original Impeller ............................................................................................. 42
3.1.2.2 New Impeller ................................................................................................... 44
3.1.2.3 Bowl Ring ........................................................................................................ 46
3.1.2.4 New Diffuser ................................................................................................... 48
3.2 New Diffuser Design ................................................................................. 51
3.2.1 New Diffuser Exit Profile ........................................................................................ 53
3.2.2 New Diffuser Design Investigations ........................................................................ 55
3.2.2.1 Diffuser Efficiency .......................................................................................... 55
3.2.2.1.1 Axial Distance ........................................................................................... 55
3.2.2.1.2 Diffuser Vane Length ................................................................................ 58
3.2.2.2 Diffuser Inlet Angle ......................................................................................... 59
3.2.2.3 Pump Speed Investigations .............................................................................. 63
3.2.2.4 Increase of Impeller Blades ............................................................................. 64
3.2.2.5 Flow Passage ................................................................................................... 65
3.3 Repair of New Diffuser ............................................................................. 67
3.3.1 Diffuser Inspection .................................................................................................. 67
3.3.2 Flow Passage Surface Repair .................................................................................. 69
3.3.3 Tail Piece Addition .................................................................................................. 70
Contents
ix
3.3.3.1 Tail Piece Manufacture ................................................................................... 73
3.3.3.1.1 3D Printing Process ................................................................................... 73
3.4 Eight Vane Impeller Repair ....................................................................... 75
3.4.1 Preliminary CMM Check ........................................................................................ 75
3.4.2 Paint Removal ......................................................................................................... 77
3.4.3 Vane Repair ............................................................................................................ 78
3.4.4 Vane Polishing ........................................................................................................ 79
3.5 Chapter Conclusion ................................................................................... 79
4 Computational Fluid Dynamics (CFD) .................................. 82
4.1 CFD Nomenclature .................................................................................... 82
4.2 CFD Introduction ....................................................................................... 83
4.2.1 Continuity Equation (Mass Transfer)...................................................................... 83
4.2.2 Momentum Equations ............................................................................................. 83
4.2.3 Total Energy Equations ........................................................................................... 83
4.2.4 Turbulence Equations ............................................................................................. 84
4.3 Research Parameters .................................................................................. 85
4.3.1 Analysis Type ......................................................................................................... 85
4.3.2 Grid Selection ......................................................................................................... 85
4.3.2.1 Mesh Size Determination ................................................................................ 88
4.3.3 Model Boundary Parameters ................................................................................... 89
4.3.3.1 Boundary Inlet Input ....................................................................................... 89
4.3.3.2 Boundary Outlet Input .................................................................................... 89
4.3.3.3 Pump Wall Boundary ...................................................................................... 90
4.3.4 Domains .................................................................................................................. 90
4.4 CFD Analysis and Results ......................................................................... 91
4.4.1 Five Vane Impeller Pump Configuration ................................................................ 91
4.4.1.1 Standard Pump Configuration Analysis .......................................................... 92
4.4.1.2 New Diffuser Configuration Analysis ............................................................ 95
4.4.1.3 Tail Piece Angle Analysis ............................................................................... 99
4.4.1.4 Predicted Pressure Rise ................................................................................. 104
4.4.2 Eight Vane Impeller Pump Configuration ............................................................ 107
4.4.2.1 Standard Pump Configuration Analysis ........................................................ 107
4.4.2.2 New Diffuser Configuration Analysis .......................................................... 109
Contents
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4.4.2.3 Tail Piece Analysis ........................................................................................ 111
4.4.2.4 Predicted Pressure Rise ................................................................................. 114
4.4.3 Analysis at Stall Flow ............................................................................................ 116
4.5 Further Analysis ...................................................................................... 117
4.5.1 Inlet Hub Modification .......................................................................................... 117
4.6 Alternative Diffuser Design Analysis ..................................................... 119
4.7 Chapter Conclusion ................................................................................. 126
5 Experimental Investigation ................................................... 128
5.1 Pump Testing........................................................................................... 128
5.1.1 Laboratory Test Rig Layout................................................................................... 129
5.1.1.1 Original Pump Test Rig ................................................................................. 129
5.1.1.2 Upgraded Refurbishment of Test Rig ............................................................ 133
5.1.2 Pump Test Configurations ..................................................................................... 134
5.1.2.1 Configurations A and B ................................................................................. 134
5.1.2.2 Configurations C and D ................................................................................. 135
5.1.2.3 Configurations E and F .................................................................................. 136
5.1.3 Test Schedule ......................................................................................................... 136
5.1.4 Test Procedure ....................................................................................................... 137
5.1.5 Test Measurements ................................................................................................ 139
5.1.5.1 Flow Measurement ........................................................................................ 141
5.1.5.2 Measurement of Pump Power Input .............................................................. 141
5.1.5.2.1 Torque Measurement ............................................................................... 141
5.1.5.3 Pump Total Head ........................................................................................... 143
5.1.5.4 Pump Speed ................................................................................................... 144
5.2 Test Results ............................................................................................. 144
5.2.1 Determine Test Base Results ................................................................................. 145
5.2.1.1 Five Vane Impeller Test: Standard Pump ...................................................... 145
5.2.1.2 Possible Reasons for Reduced Test Performance Results ............................. 149
5.2.1.2.1 Impeller Bowl Ring Leakage ................................................................... 149
5.2.1.2.2 Reduced Impeller Cord Length ............................................................... 149
5.2.1.3 Eight Vane Impeller Test: Standard Pump .................................................... 150
5.2.2 Pump Test with New Diffuser ............................................................................... 154
5.2.2.1 Five Vane Impeller tests ................................................................................ 155
Contents
xi
5.2.2.2 Eight Vane Impeller Tests ............................................................................. 157
5.2.3 Pump Test with Tail piece Addition ..................................................................... 159
5.2.3.1 Five Vane Impeller Tests .............................................................................. 159
5.2.3.2 Eight Vane Impeller Tests ............................................................................. 163
5.3 Chapter Conclusion ................................................................................. 166
6 Summary, Findings and Future Work .................................. 168
6.1 Research Summary .................................................................................. 168
6.2 Research Findings .................................................................................... 169
6.3 Future Work ............................................................................................. 171
7 Bibliography ......................................................................... 172
Appendix A. Detailed Calculations ......................................... 175
A.1. Detailed Calculations ............................................................................... 175
A.2. Five Vane Impeller Velocity Calculations .............................................. 175
Velocity Calculations for Five Vane Impeller .................................................. 176 A.2.1.
Velocity Triangles for Five Vane Impeller ....................................................... 177 A.2.2.
Comparisons of Impeller Outlet Angles to New Diffuser Inlet Angles ............ 178 A.2.3.
A.3. Six Vane Impeller Velocity Calculations ................................................ 179
Velocity Calculations for Six Vane Impeller .................................................... 180 A.3.1.
Velocity Triangles for Six Vane Impeller ......................................................... 181 A.3.2.
Comparisons of Impeller Outlet Angles to New Diffuser Inlet Angles ............ 182 A.3.3.
A.4. Eight Vane Impeller Velocity Calculations ............................................. 182
Calculations for Eight Vane Impeller ............................................................... 184 A.4.1.
Velocity Triangles for Eight Vane Impeller ...................................................... 185 A.4.2.
Comparisons of Eight Vane Impeller Outlet Angles to New Diffuser Inlet AnglesA.4.3.
186
A.5. Speed Increase ......................................................................................... 187
Results ............................................................................................................... 187 A.5.1.
Appendix B. Test Rig Assembly and Disassembly ................. 191
B.1. Initial Pump Rig Observations ................................................................ 191
Contents
xii
B.2. Pump Disassembly Steps ........................................................................ 191
Complete Pump Disassembly ............................................................................ 191 B.2.1.
Impeller Change Over ....................................................................................... 193 B.2.2.
B.3. Pump Assembly Steps ............................................................................. 194
Pump Reassembly Steps .................................................................................... 194 B.3.1.
Installation of Impeller only .............................................................................. 196 B.3.2.
B.4. Test Rig Tool Improvements .................................................................. 196
Opening and Closing the Pump ......................................................................... 196 B.4.1.
Impeller Installation and Removal..................................................................... 197 B.4.2.
B.5. Pump Laboratory Issues .......................................................................... 198
Rubber Gaskets and Debris ............................................................................... 199 B.5.1.
Pump Sealing and Leaking ................................................................................ 199 B.5.2.
Test Rig Straightening Tubes ............................................................................ 200 B.5.3.
Pump Assembly ................................................................................................. 200 B.5.4.
Appendix C. Ultrasonic Flow Meter ........................................ 202
C.1. Sound Path............................................................................................... 204
C.2. Flow Measurement Recording ................................................................ 205
Appendix D. Laboratory Test Data .......................................... 207
D.1. Pump Tests 1 ........................................................................................... 207
Tests 1.01 and 1.02 ............................................................................................ 207 D.1.1.
Test 1.03 ............................................................................................................ 208 D.1.2.
Tests 1.04 and 1.05 ............................................................................................ 210 D.1.3.
Tests 2.02 and 2.03 ............................................................................................ 213 D.1.4.
Tests 3.01 and 3.02 ............................................................................................ 215 D.1.5.
Tests 4.01 and 4.02 ............................................................................................ 218 D.1.6.
Tests 4.03 and 4.04 ............................................................................................ 220 D.1.7.
Tests 5.01 and 5.02 ............................................................................................ 223 D.1.8.
Tests 6.01, 6.02 and 6.03 ................................................................................... 225 D.1.9.
Appendix E. CFD Models ........................................................ 228
E.1. Standard Pump Initial CFD Analysis ...................................................... 228
Contents
xiii
E.2. New Diffuser with Elongated Tail piece ................................................. 230
E.3. Complete Diffuser Design ....................................................................... 231
Appendix F. Coordinate Measurement Machine ..................... 237
Appendix G. Coating Data Sheet ............................................. 239
Appendix H. Tachometer Technical Sheet .............................. 241
Appendix I. 3D Printer Data Sheet .......................................... 243
Appendix J. Drawings .............................................................. 245
C163 – Impellers all Sizes, General Blade Forms
C168 – Thin Blade Impellers Section Dimensions
C269 – No. 8 impeller Blade Section Dimensions
C277 – Bowl Vane Dimensions type 3-4-5-6
C400 – Bowl Vane 6-7-8
UTS0001 – Exit Profile Addition
UTS0002 – Adaptor
UTS0003 – Assembly Cone Piece
UTS0004 – Proposed Modification (New Diffuser)
UTS0005 – Collet Drive
UTS0006 – Tail Piece, Base
UTS0007 – Tail Piece, Top
UTS0008 – Tail Piece Assembly
List of Figures Figure 1 – Pump Classification Tree ............................................................................................. 3
Figure 2 – Specific Speed vs. Efficiency (Australian Pump Handbook, 2004) ............................ 4
Figure 3- Specific Speed Graph (Stepanoff, 1957) pg76 .............................................................. 5
Figure 4 – Flow Direction Axial Flow Pumps .............................................................................. 6
Contents
xiv
Figure 5 – 450AX ‘Ornel’ pump, for water transfer (Installation by Weir Minerals Australia) ... 7
Figure 6 - 400AX ‘Ornel’ pump, for water transfer (Installation by Weir Minerals Australia) .... 7
Figure 7 – Portable Ornel 300AX pump (Manufactured by Weir Minerals Australia) ................. 8
Figure 8– Typical Arrangement of an Ornel Axial Flow Pumps (Nelson, n.d.) ........................... 9
Figure 9 – Existing pump used in this research. .......................................................................... 10
Figure 10 – Suction Bell used in the research ............................................................................. 10
Figure 11 – Recommended Bell Diameter (Institute, 1994) pg30 ............................................... 11
Figure 12 – Five vane open impeller used in the research .......................................................... 12
Figure 13 – Vane Angle .............................................................................................................. 12
Figure 14 – Stator and Diffuser arrangement .............................................................................. 14
Figure 15 – Original Pump Curve for a 300AX ‘Ornel’ pump running at a speed of 1465rpm
(Weir Minerals Australia 1990). .................................................................................................. 15
Figure 16 – Typical Axial Flow Pump performance curve - sourced from (Lazarkiewicz, 1965)
pg404 ........................................................................................................................................... 16
Figure 17 – One-dimensional flow through an Axial Flow Pump impeller (Lazarkiewicz, 1965)
pg222 ........................................................................................................................................... 19
Figure 18 – Development of an Ornel five vane impeller ........................................................... 20
Figure 19 – Velocity triangles for single pump stage (Kovats, 1964) pg91 ................................ 20
Figure 20 – Velocity triangle at impeller inlet and outlet (Kovats, 1964) pg91 .......................... 21
Figure 21 – (a) Flow of a streamline in plane xz (b) Streamline coordinates (Munson, 2013)
pg100 ........................................................................................................................................... 22
Figure 22 – Airfoil description (Stepanoff, 1957) pg140 ............................................................ 23
Figure 23 – Pressure generated on impeller blade surfaces ......................................................... 24
Figure 24 – Forces acting on an airfoil Blade (Stepanoff, 1957) pg140 ..................................... 24
Figure 25 – Turbulence Formation .............................................................................................. 26
Figure 26 – Secondary flow within an Axial Flow Pump Impeller (Brennen, 1994) pg71 ......... 26
Figure 27 – Flow field at vane tip (Farrell, 1989) pg4 ................................................................ 27
Figure 28 – Impeller to bowl ring leakage (Stepanoff, 1957) pg202 .......................................... 27
Figure 29 – Pump stall ................................................................................................................. 28
Contents
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Figure 30 – Pump curve stall line ............................................................................................... 28
Figure 31 – Hub ratio for number of vanes and l/t ratio (Stepanoff, 1957) pg145 ..................... 29
Figure 32 – Extended hub ratio chart showing pump used in this research ................................ 30
Figure 33 – Vane length reduction (Dicmas, 1987) pg108 ......................................................... 31
Figure 34 – Change in pump performance (Dicmas, 1987) pg109 ............................................. 31
Figure 35 – Original Ornel pump design of a stator followed by diffuser .................................. 32
Figure 36 – Loss coefficient for a diffuser (Munson, 2013) pg435 ............................................ 32
Figure 37 – Velocity triangle at impeller outlet at a streamline .................................................. 33
Figure 38 – Detail of velocity triangle at impeller outlet and angle of guide vane inlet ............. 33
Figure 39 – Diffuser design variables (Stepanoff, 1957) pg159 ................................................. 34
Figure 40 – Velocity diagram at diffuser inlet (Stepanoff, 1957) pg157 .................................... 34
Figure 41 – Recommended impeller vane outlet to guide vane inlet, design distance ............... 35
Figure 42 – Comparison of two identical pumps with different diffusers (Lazarkiewicz, 1965) 36
Figure 43 – Previous research five vane impeller test results ..................................................... 37
Figure 44 – Comparison of test configuration ‘A’ of previous and current research of a five vane
impeller standard pump (error bars set at 8%) ............................................................................ 38
Figure 45 – CMM (Faro arm) ..................................................................................................... 40
Figure 46 – CMM measurement of new impeller ....................................................................... 40
Figure 47 – Centre of probe to surface contact (Hi-Tech, 2010) pg3 ......................................... 41
Figure 48 – Field of view of laser probe (FARO Technologies, 2008) ...................................... 41
Figure 49 – Scan of Impeller....................................................................................................... 42
Figure 50 – 3D Model of scanned impeller ................................................................................ 43
Figure 51 – Overlay of scan onto design model ......................................................................... 43
Figure 52 – Comparison of impeller scan to model of original design impeller. ....................... 44
Figure 53 – Reduction distance of trailing edge ......................................................................... 44
Figure 54 – New impeller set-up and laser scanned image ......................................................... 45
Figure 55 – Measurement of new impeller outside diameter ...................................................... 45
Figure 56 – Bowl ring CMM measurements .............................................................................. 46
Figure 57 – Bowl ring runout checks .......................................................................................... 47
Contents
xvi
Figure 58 – Scan image of new diffuser ...................................................................................... 48
Figure 59 – 3D CAD model of diffuser ....................................................................................... 49
Figure 60 – Comparison Inlet Vane Tip ...................................................................................... 50
Figure 61 – Comparison Outlet Vane Tip ................................................................................... 50
Figure 62 – New diffuser design, stator and diffuser combined. ................................................. 51
Figure 63 – Velocity streamline in a standard design ‘Ornel’ pump at midstream line, showing
recirculation between diffuser vanes. .......................................................................................... 52
Figure 64 – Mixed flow pump flow direction ............................................................................. 52
Figure 65 – New diffuser flow direction ..................................................................................... 53
Figure 66 – Sudden enlargement (Munson, 2013) pg435 ........................................................... 54
Figure 67 – Area measurement of diffuser outlet ........................................................................ 54
Figure 68 – New diffuser CFD velocity streamline on single plane ........................................... 54
Figure 69 – Comparison of dimensions ....................................................................................... 55
Figure 70 - Original standard 300AX pump configuration ......................................................... 56
Figure 71 – Measured axial distance during pump assembly between original stator and the five
vane impeller ............................................................................................................................... 56
Figure 72 – Pump arrangement with new diffuser. ..................................................................... 57
Figure 73 – Suction case spacer addition .................................................................................... 57
Figure 74 – Possible modifications to new diffuser .................................................................... 58
Figure 75 – Diffuser vane distance from impeller centre for original pump ............................... 58
Figure 76 - Diffuser vane distance from impeller centre for new diffuser design ....................... 59
Figure 77 – Blade profiles for a five vane impeller ..................................................................... 59
Figure 78 – New diffuser vane profile ......................................................................................... 60
Figure 79 – Mid stream velocity triangles for 6 vane impeller and standard ‘Ornel’ type VII
bowl (stator)................................................................................................................................. 60
Figure 80 – Mid streamline velocity triangles for five vane impeller and new diffuser ............. 61
Figure 81 – Mid stream velocity triangles for 6 vane impeller and new diffuser ........................ 62
Figure 82 – Performance curve showing speed increase at 1465, 1495 and 1525 rpm using a five
vane impeller ............................................................................................................................... 64
Contents
xvii
Figure 83 - Mid stream velocity triangles for eight vane impeller and new diffuser .................. 65
Figure 84 – Original Ornel type 5 bowl flow passage measurements ........................................ 66
Figure 85 – New diffuser flow passage measurements ............................................................... 66
Figure 86 – Flow passage area comparison ................................................................................ 67
Figure 87 – Removed diffuser pre-repairs .................................................................................. 68
Figure 88 – Rust build-up and paint flaking on guide vane inlet ................................................ 68
Figure 89 – Diffuser surfaces after sand blasting........................................................................ 69
Figure 90 – Coating being applied to surface ............................................................................. 70
Figure 91 – Completed coated diffuser internals ........................................................................ 70
Figure 92 – New diffuser exit area .............................................................................................. 71
Figure 93 – CFD comparison of pump with and without 20º tail piece ..................................... 72
Figure 94 – Tail Piece addition to diffuser exit profile ............................................................... 72
Figure 95 - Stages of the build process (Hiemenz, 2014) pg2 .................................................... 73
Figure 96 – 3D printed tail piece ................................................................................................ 74
Figure 97 – 3D print surface before sanding ............................................................................... 74
Figure 98 – Sanding 3D print surface ......................................................................................... 74
Figure 99 – Painted eight vane impeller ..................................................................................... 75
Figure 100 – Damage to outlet vane tips. ................................................................................... 75
Figure 101 – CMM scan of eight vane impeller vane ................................................................. 76
Figure 102 – Overlay of scan to 3D model ................................................................................. 76
Figure 103 – Overlay showing vane profile ................................................................................ 77
Figure 104 – Bead blasting the impeller to remove paint. .......................................................... 77
Figure 105 – Uncovered vane face damage ................................................................................ 78
Figure 106 – Repair of damaged vane tips ................................................................................. 78
Figure 107 – SST model blend for accurate turbulence prediction (ANSYS Inc, 2013) pg18
Lecture 7 ..................................................................................................................................... 85
Figure 108 – Types of mesh elements (ANSYS, 2013) lecture 10 pg. 33 ................................. 86
Figure 109 – Split plane of model’s flow area mesh .................................................................. 86
Figure 110 – Grid inflation at wall boundary (Tu, 2008) pg.239 ............................................... 87
Contents
xviii
Figure 111 – Internal mesh zoomed view ................................................................................... 87
Figure 112 – Mesh sizing check .................................................................................................. 89
Figure 113 – Model domains ....................................................................................................... 90
Figure 114 – Rotating frame of reference (ANSYS Inc, 2013) pg34 .......................................... 91
Figure 115 - CFD model of original pump configuration with five vane impeller ..................... 91
Figure 116 - CFD analysis of original pump configuration with five vane impeller .................. 92
Figure 117 - Enlarged view of blade outlet area from Figure 116 .............................................. 93
Figure 118 – Original pump stator design (from Weir Engineering drawing) ............................ 93
Figure 119 - Original pump configuration 3D streamline ........................................................... 93
Figure 120 – Original five vane pump total pressure prediction ................................................. 94
Figure 121 – Predicted pressure rise through std. diffuser .......................................................... 94
Figure 122 - CFD analysis of new diffuser pump configuration with five vane impeller ........... 95
Figure 123 - Enlarged view of blade outlet area from Figure 122 .............................................. 96
Figure 124 – New diffuser pump configuration 3D streamline ................................................... 96
Figure 125 – Comparison of standard pump and new diffuser design ........................................ 97
Figure 126 – 300AX impeller drawing (Weir Minerals Australia) ............................................. 97
Figure 127 – Addition of open area to impeller model ............................................................... 98
Figure 128 – Modified model 2D streamline .............................................................................. 98
Figure 129 – New Diffuser five vane pump total pressure prediction......................................... 99
Figure 130 – Determination of start angle for analysis ............................................................. 100
Figure 131 – The different CFD models analysed. Range from the new diffuser with tail piece
added at various angles. ............................................................................................................. 100
Figure 132 – 2D streamlines of tail piece angle analysis .......................................................... 101
Figure 133 – CFD analysis of tail piece addition configuration with five vane impeller .......... 102
Figure 134 – Enlarged view of blade outlet area from Figure 133 ............................................ 103
Figure 135 – Comparison of new diffuser and tail piece addition 3D streamline ..................... 103
Figure 136 - Predicted outlet pressure for tail piece addition, plane plot at probe point ........... 104
Figure 137 – Planes created for pressure section measurements ............................................... 105
Figure 138 - Predicted pressure through new diffuser with five vane impeller ........................ 105
Contents
xix
Figure 139 - Predicted pressure rise through new diffuser ....................................................... 106
Figure 140 – Predicted pressure rise through new diffuser with tail piece ............................... 106
Figure 141 - CFD analysis of original pump configuration with eight vane impeller .............. 107
Figure 142 - Enlarged view of blade outlet area from Figure 141 ............................................ 107
Figure 143 - Original pump configuration 3D streamline ........................................................ 108
Figure 144 – Overlay of velocity streamline and total pressure ............................................... 108
Figure 145 – Original eight vane pump pressure prediction ..................................................... 109
Figure 146 - CFD analysis of new diffuser pump configuration with eight vane impeller ...... 109
Figure 147 - Enlarged view of blade outlet area from Figure 146 ............................................ 110
Figure 148 - New diffuser pump configuration 3D streamline ................................................. 110
Figure 149 – Predicted pressure at new diffuser outlet ............................................................. 111
Figure 150 - CFD analysis of tail piece addition configuration with eight vane impeller ........ 112
Figure 151 - Enlarged view of blade outlet area from Figure 150 ............................................ 112
Figure 152 - Predicted outlet pressure for tail piece addition ................................................... 112
Figure 153 – Comparison of new diffuser and tail piece addition 3D streamline .................... 114
Figure 154 - Predicted pressure rise through new diffuser ....................................................... 114
Figure 155 - Predicted pressure rise through new diffuser with tail piece ................................ 115
Figure 156 - Predicted pressure through new diffuser with eight vane impeller ...................... 115
Figure 157 – Test comparison 2D velocity streamlines at 234 L/s ........................................... 116
Figure 158 – Test comparison total pressure at 234 L/s ........................................................... 117
Figure 159 – Impeller hub face open area model modification ................................................ 118
Figure 160 – Impeller hub face open area model modification 3D streamline ......................... 118
Figure 161 – Layout of diffuser re-design number 1 ................................................................ 120
Figure 162 - Layout of diffuser re-design number 2 ................................................................. 120
Figure 163 – Layout of diffuser re-design number 3 ................................................................ 121
Figure 164 – Layout of diffuser re-design number 4 ................................................................ 121
Figure 165 – Flow passage area measurements ........................................................................ 122
Figure 166 – 2D velocity streamlines of re-designed diffuser .................................................. 123
Contents
xx
Figure 167 – Total pressure plots for re-designed diffuser ........................................................ 124
Figure 168 – 3D velocity streamline plots for re-designed diffuser .......................................... 125
Figure 169 – Refurbished hydraulics laboratory pump test rig at UTS ..................................... 129
Figure 170 – Test Rig Layout .................................................................................................... 130
Figure 171 – Straightener pipe section ...................................................................................... 130
Figure 172 – Pipe internals showing straightener section ......................................................... 131
Figure 173 – Pump installation arrangement for Test no.1 ....................................................... 131
Figure 174 – Main air release valve chamber ............................................................................ 132
Figure 175 – Throttle Valve ...................................................................................................... 133
Figure 176 – Upgraded test rig .................................................................................................. 134
Figure 177 – New control panel ................................................................................................ 134
Figure 178 – Pump assembly configurations A & B ................................................................. 135
Figure 179 – Pump assembly configuration C & D .................................................................. 135
Figure 180 – Pump assembly configuration E & F ................................................................... 136
Figure 181 – Pressure release valve .......................................................................................... 137
Figure 182 – Valve notch indicator (a) full notch (b) half notch ............................................... 138
Figure 183 – Conducting test 5.01 ............................................................................................. 139
Figure 184 – Blank pump test sheet .......................................................................................... 140
Figure 185 – Plummer block supports ....................................................................................... 141
Figure 186 – Arm and force gauge ............................................................................................ 142
Figure 187 – Test rig VSD ........................................................................................................ 142
Figure 188 – Digital pressure gauges ........................................................................................ 143
Figure 189 – Mercury manometer and replacement hand held manometer .............................. 144
Figure 190 – Comparison of Pump Tests 1.04 and 1.05 ........................................................... 147
Figure 191 - Test 1.04 Pump Test Performance Curve ............................................................. 148
Figure 192 – Difference in impeller chord length ..................................................................... 149
Figure 193 – Difference in impeller shape ................................................................................ 150
Figure 194 – Original pump assembly ...................................................................................... 152
Contents
xxi
Figure 195 - Test 2.02 pump test performance curve ............................................................... 153
Figure 196 – Impeller running gap check, new diffuser installation ........................................ 154
Figure 197 – Installed pump with new diffuser ........................................................................ 154
Figure 198 – Five vane impeller base test to new diffuser comparison .................................... 156
Figure 199 - Pump test results 4.03........................................................................................... 157
Figure 200 - Eight vane impeller base test to new diffuser comparison ................................... 158
Figure 201 – Preassembly of tail piece, in two steps ................................................................ 159
Figure 202 – Tail piece assembly ............................................................................................. 159
Figure 203 – Impeller running gap check for five vane impeller.............................................. 160
Figure 204 - Test 5.02 performance curve ................................................................................ 161
Figure 205 - Five vane impeller, base test to new diffuser and tail piece comparison ............. 162
Figure 206 - Test 6.01 performance curve ................................................................................ 164
Figure 207 - Eight vane impeller, base test to new diffuser and tail piece comparison ............ 165
Figure 208 – Impeller streamlines ............................................................................................ 175
Figure 209 - Overlay of five vane impeller AA, BB & CC streamlines ................................... 175
Figure 210 – Velocity Triangle, Streamlines AA, BB & CC, Five Vane Impeller Inlet .......... 177
Figure 211- Velocity Triangle, Streamlines AA, BB & CC, Five Vane Impeller Outlet ......... 177
Figure 212 – Streamline AA of five vane impeller and new diffuser inlet ............................... 178
Figure 213 - Overlay of impeller no.6 AA, BB & CC streamlines ........................................... 179
Figure 214 - Velocity Triangle, Streamlines AA, BB & CC, Six Vane Impeller Inlet ............. 181
Figure 215 - Velocity Triangle, Streamlines AA, BB & CC, Six Vane Impeller Outlet .......... 181
Figure 216 – Streamline AA of Six vane impeller and new diffuser inlet ................................ 182
Figure 217 - Overlay of Eight Vane Impeller AA, BB & CC streamlines ............................... 183
Figure 218 – Velocity Triangle, Streamlines AA, BB & CC, Eight Vane Impeller Inlet ......... 185
Figure 219 - Velocity Triangle, Streamlines AA, BB & CC, Eight Vane Impeller Outlet ....... 185
Figure 220 - Streamline AA of eight vane impeller and new diffuser inlet .............................. 186
Figure 221 – Comparison of velocity triangles running at 1465 rpm and 1525 rpm. ............... 188
Figure 222 – Performance curve showing speed increase at 1465, 1495 and 1525 rpm .......... 189
Contents
xxii
Figure 223 – Open dismantling joint ......................................................................................... 191
Figure 224 – Pump assembly..................................................................................................... 192
Figure 225 – Attachment of cable winch ................................................................................... 192
Figure 226 – Removal of suction case ....................................................................................... 193
Figure 227 – Impeller Removal ................................................................................................. 193
Figure 228 – Diffuser and tail piece installation ....................................................................... 194
Figure 229 – Impeller installation ............................................................................................. 195
Figure 230 – Lever to close pump assembly ............................................................................. 195
Figure 231 – Assembled dismantling joint ................................................................................ 196
Figure 232 – Stud and nut collet removal .................................................................................. 197
Figure 233 – Backing plate modification .................................................................................. 197
Figure 234 – Collet drive ........................................................................................................... 198
Figure 235 – Damaged sealing face of bowl ring ...................................................................... 199
Figure 236 – Leakage and repair at spool piece ........................................................................ 200
Figure 237 – Impeller installation with no running gap ............................................................ 201
Figure 238 – Damage to new diffuser ....................................................................................... 201
Figure 239 – Path of Ultrasonic Signal (User Manual UMF601V1-1EN Ultrasonic Flowmeter,
2008) .......................................................................................................................................... 202
Figure 240 – Transit time difference (User Manual UMF601V1-1EN Ultrasonic Flowmeter,
2008) .......................................................................................................................................... 202
Figure 241 – Ultrasonic flowmeter installation ......................................................................... 203
Figure 242 – Flowmeter transducer sound path ........................................................................ 204
Figure 243 – Mounting of transducer ........................................................................................ 205
Figure 244 – Flow data for test 1-01. ........................................................................................ 205
Figure 245 – Test point 1, test 1-01 ........................................................................................... 205
Figure 246 – Flow results test points for test 1-01 .................................................................... 206
Figure 247 – Test curve, Tests 1-01 and 1-02 ........................................................................... 208
Figure 248 – Pump test curve 1.03 ............................................................................................ 210
Figure 249 - Comparison of pump tests 1.04 and 1.05 .............................................................. 212
Contents
xxiii
Figure 250 - Comparison of pump tests 2.02 and 2.03 ............................................................. 214
Figure 251 - Comparison of pump tests 3.01 and 3.02 ............................................................. 216
Figure 252 - Test 3.02 performance curve compare to original design. ................................... 217
Figure 253 - Comparison of pump tests 4.01 and 4.02 ............................................................. 219
Figure 254 - Comparison of pump tests 4.03 and 4.04 ............................................................. 221
Figure 255 - Test 4.03 performance curve compared to original design curve ........................ 222
Figure 256 – Comparison of pump tests 5.01 and 5.02 ............................................................ 224
Figure 257 - Comparison of pump tests 6.01, 6.02 and 6.03 .................................................... 227
Figure 258 – STT analysis, fine mesh, inlet: mass flow rate, outlet: 90 kPa, probe pressure point
suction: 23.6 kPa, discharge: 94.1 kPa ...................................................................................... 228
Figure 259 – k-e analysis, medium mesh, inlet: mass flow rate, outlet: 90 kPa, point probe point
suction: 27 kPa, discharge: 93 kPa............................................................................................ 228
Figure 260 - k-e analysis, coarse mesh, inlet: mass flow rate, outlet: 90 kPa, point probe point
suction: 27.5 kPa, discharge: 93.5 kPa ...................................................................................... 229
Figure 261 - SST analysis, fine mesh, inlet: mass flow rate, outlet: mass flow rate, point probe
point suction: -48.5 kPa, discharge: 22.6 kPa ........................................................................... 229
Figure 262 - SST analysis, fine mesh, inlet: mass flow rate, outlet: 90 kPa, point probe point
suction: 23.6 kPa, discharge: 94.14 kPa .................................................................................... 229
Figure 263 - SST analysis, fine mesh, inlet: 100 kPa, outlet: mass flow rate, point probe point
suction: 100 kPa, discharge: 172.1 kPa ..................................................................................... 230
Figure 264 – Elongated tail piece 2D velocity streamlines ....................................................... 230
Figure 265 –Elongated tail piece total pressure and 2D velocity streamlines .......................... 231
Figure 266 – 2D velocity streamline plot for new design number 1 ......................................... 231
Figure 267 – Total pressure plot for new design number 1 ...................................................... 231
Figure 268 – New design number 1, shroud and hub outline ................................................... 232
Figure 269 – Vane profile for new design number 1 ................................................................ 232
Figure 270 – Vane profile alignment design number 1............................................................. 233
Figure 271 - New design number 2, shroud and hub outline .................................................... 233
Figure 272 - 2D velocity streamline plot for new design number 2 ......................................... 234
Figure 273 – Total pressure plot for new design number 2 ...................................................... 234
Contents
xxiv
Figure 274 – Zoom view of Figure 273 ..................................................................................... 234
Figure 275 - New design number 3, shroud and hub outline ..................................................... 235
Figure 276 - Vane profile for new design number 3 ................................................................. 235
Figure 277 - 2D velocity streamline plot for new design number 3 .......................................... 236
Figure 278 – Total pressure plot for new design number 3 ....................................................... 236
Figure 279 - Zoom view of Figure 278 ..................................................................................... 236
Figure 280 – Coating data sheet ................................................................................................ 240
List of Tables Table 1 – Impeller to stator assembly .......................................................................................... 13
Table 2 – Comparison of five vane impeller outlet velocity to new diffuser inlet ...................... 61
Table 3 - Comparisons of 6 vane impeller outlet velocity to new diffuser inlet ......................... 62
Table 4 – Comparison of an eight vane impeller to the new diffuser .......................................... 65
Table 5 - Standard CFX medium mesh parameters ..................................................................... 88
Table 6 – Re-designed diffuser predicted total pressure ........................................................... 122
Table 7 – Pump test configurations ........................................................................................... 128
Table 8 – Pump test schedule .................................................................................................... 136
Table 9 – Pump Test Results 1.04 ............................................................................................. 146
Table 10 - Pump test results 2.02 .............................................................................................. 151
Table 11 - Pump test results 3.02 .............................................................................................. 155
Table 12 - Pump test results 5.02 .............................................................................................. 160
Table 13 - Pump test results 6.01 .............................................................................................. 163
Table 14 –Five vane impeller pump test comparison to base test ............................................. 166
Table 15 - Eight vane impeller pump test comparison to base test ........................................... 167
Table 16 – Five vane impeller velocity calculations ................................................................. 176
Table 17 – Six Vane Impeller inlet velocity calculations .......................................................... 180
Table 18 – Eight Vane Impeller inlet velocity calculations....................................................... 184
Table 19 - Calculations of number eight impeller angles α2 and β3 at 1465rpm ....................... 186
Contents
xxv
Table 20 – Calculations of angles α2 and β3 at 1465, 1495 and 1525 rpm ................................ 187
Table 21 – Calculations for an increase in pump speed, for 1465, 1495, 1525 and 2000 rpm . 190
Table 22 – Pump test 1.01 ......................................................................................................... 207
Table 23 – Pump test 1.02 ......................................................................................................... 207
Table 24 – Pump test 1.03 ......................................................................................................... 209
Table 25 – Pump test results 1.04 ............................................................................................. 211
Table 26 – Pump test results 1.05 ............................................................................................. 211
Table 27 - Pump test results 2.02 .............................................................................................. 213
Table 28 - Pump test results 2.03 .............................................................................................. 213
Table 29 - Pump test results 3.01 .............................................................................................. 215
Table 30 - Pump test results 3.02 .............................................................................................. 215
Table 31 - Pump test results 4.01 .............................................................................................. 218
Table 32 - Pump test results 4.02 .............................................................................................. 218
Table 33 - Pump test results 4.03 .............................................................................................. 220
Table 34 - Pump test results 4.04 .............................................................................................. 220
Table 35 - Pump test results 5.01 .............................................................................................. 223
Table 36 - Pump test results 5.02 .............................................................................................. 223
Table 37 - Pump test results 6.01 .............................................................................................. 225
Table 38 - Pump test results 6.02 .............................................................................................. 225
Table 39 - Pump test results 6.03 .............................................................................................. 226